The field of the disclosure relates generally to wind turbines and, more particularly, to compact drivetrain assemblies for wind turbines.
Wind turbines have received increased attention as environmentally safe and relatively inexpensive alternative energy sources. Wind turbines do not emit greenhouse gases (GHGs) and, therefore, do not contribute to global warming. With the growing interest in wind generated electricity, considerable efforts have been made to develop wind turbines that are reliable and efficient.
Wind is usually considered to be a form of solar energy caused by uneven heating of the atmosphere by the sun, irregularities of the Earth's surface, and rotation of the Earth. Wind flow patterns are modified by the Earth's terrain, bodies of water, and vegetation. The terms “wind energy” and “wind power” describe a process by which wind is used to rotate a shaft and subsequently generate mechanical power or electricity.
Some known wind turbines are used to convert the kinetic energy in the wind into mechanical power. This mechanical power may be used for specific tasks (such as grinding grain or pumping water) or a generator may convert this mechanical power (i.e., the rotation of a shaft) into electricity. A wind turbine usually includes an aerodynamic mechanism (e.g., blades) for converting the movement of air into a mechanical motion (e.g., rotation), which is then converted with a generator into electrical power. Power output from the generator is proportional to the cube of the wind speed. As wind speed doubles, the capacity of wind generators increases almost eightfold.
Some known, commercially available wind turbines utilize geared drivetrains to connect the turbine blades to the electrical generators. The wind turns the turbine blades, which spin a low speed shaft, which feeds into a gearbox having a higher speed output shaft. This higher speed output shaft connects to a generator and makes electricity. The geared drive aims to increase the velocity of the mechanical motion.
The industry standard drivetrain for large (e.g., >1 Mega-watt (MW)) wind turbines consists of discrete gearbox and generator units that are separately mounted to a mainframe (also commonly called a bedframe or bedplate). Power is transferred from the gearbox to the generator via a flexible “high-speed” shaft coupling. This arrangement forces the gearbox and the generator to be physically distanced from each other, as well as requires both the output shaft of the gearbox and the input shaft of the generator to be separately supported by gearbox bearings and generator bearings, respectively.